We are studying the smooth pursuit eye movement system by means of physiological and psychophysical techniques. To date, we have shown the involvement of target position and target velocity (both actual and perceived) in controlling smooth pursuit eye movements. In the next part of our work, we: 1. Attempt to show the role of target position and velocity under normal stimulus conditions (closed-loop), and 2. Attempt to determine the detailed characteristics of the position and velocity mechanisms. 3. Investigate the predictive capacities of the smooth pursuit system.